Filter unit

ABSTRACT

A filter unit for separating solids from liquids comprising filter elements each consisting of two dished diaphragm sections of fine mesh material, each section having an inner and outer rim portions with an inclined annular portion adjacent thereto and a series of radial ribs in the area between said inclined portions to stiffen the section. One or more of the filter elements is mounted upon a tubular core having openings adjacent the lowermost section of the filter unit for effecting maximum drainage of liquid from the filter unit. The core is threaded at its lower end for mounting upon an outlet fitting in a housing. A handle is attached to the upper end of the core to facilitate mounting and removal of the filter unit from the housing.

D United States Patent 1 3,666,107 Boggs et a]. 5] May 30, 1972 1 FILTERUNIT 3,297,161 1/1967 Kasten ..210/114 3 312 351 4/1967 Kasten..

[72] Inventors: Weldon C. Boggs, Tampa; Charles A. Turcone Daytona c boh of Fl 3,231,094 H1 966 Wlegand ..210/487 [73] Assignee: Food Research& Equipment Company, Examiner-Frank P J Tampa, Fl AttorneyBacon andThomas [22] Filed: Sept. 17, 1970 [57] ABSTRACT Appl. No.: 73,015

A filter unit for separating solids from liquids comprising filterelements each consisting of two dished diaphragm sections of fine meshmaterial, each section having an inner and outer rim portions with aninclined annular portion adjacent thereto and a series of radial ribs inthe area between said inclined portions to stiffen the section One ormore of the filter elements is mounted upon a tubular core havingopenings adjacent the lowermost section of the filter unit for effectingmaximum drainage of liquid from the filter unit. The core is threaded atits lower end for mounting upon an outlet fitting in a housing. A handleis attached to the upper end of the core to facilitate mounting andremoval of the filter unit from the housing.

12 Claims, 6 Drawing Figures PATENTEDMAY 30 I972 $666,107

sum 1 or 2 HWTJN'I'ORS WELDO/V C. 50665 CHARLES & 75/?00175 FIELD OF THEINVENTION This invention relates to filters and more particularly to anew filter unit for removing solids from liquids. More specifically, thepresent filter is particularly useful in deep fat fryers forcontinuously filtering cooking oil to remove residue, such as, breadcrumbs, batter, food particles, etc., from the oil. As is well known, ifthe residue is not removed from cooking oil, such residue will sooncarbonize and discolor the oil, and greatly shorten its useful life.However, it is to be understood that the present filter unit is notlimited in its use to filtering cooking oil, but can be used forfiltering other liquids with equal efiectiveness.

DESCRIPTION OF THE PRIOR ART Various types of filters and materials havebeen heretofore used for filtering cooking oil and the like, but thesehave not been entirely satisfactory. A filter including a bag made fromOsnaburg cloth, does an acceptable job, but has a limited useful lifeand does not remove the very fine particles from the coking oil and,therefore, a more durable and effective filter is desirable.

SUMMARY OF THE INVENTION The present filter unit overcomes the foregoingobjections in that the filter element is made of closely woven stainlesssteel screen material preferably coated with TEFLON and capable ofremoving food particles as small as about 100 microns. The filter unitmay comprise one or more filter elements mounted upon a tubular steelcore, the core being closed at one end and threaded at its other end formounting upon a fitting in a housing or filter bowl. Each filter elementcomprises upper and lower diaphragm-like sections of frustoconical ordished formation arranged with their dished sides in confrontingrelation. The uppermost and lowermost sections in a multi-element filterunit have flat marginal rim portions that are connected with a stainlesssteel disc and ring, respectively, mounted on the core, and theintermediate sections are welded or fused together at their adjacentinner and outer flat marginal rim portions, the inner marginal portionsbeing radially spaced from the core. Openings are formed in the corewhich communicate with the interior of the filter elements, thusenabling the filtered liquid to flow through the core. Each filtersection is reinforced against distortion and collapse by inner and outerannular portions inclined at an angle to the plane of the filterelement, and by radially disposed reinforcing ribs located in the areabetween said inclined annular portions.

Accordingly, the principal object of the invention is to provide afilter element that is effective for removing very fine solids fromliquids, and which is non-corrosive and easy to clean.

Another object is to provide a filter element that can be combined withany desired number of similar filter elements to provide a filter unitof any desired capacity.

Another object is to provide a filter unit that is of ruggedconstruction and has a long life, thereby avoiding the expense offrequent replacement.

A further object is to provide a filter unit that includes a built-inhandle so that the unit can be readily installed and removed from ahousing for cleaning or inspection purposes.

A still further object is to provide a filter unit that can be drainedof all liquid prior to removal from its housing.

A still further object is to provide a filter unit that is especiallyadapted for continuously filtering cooking oil in a deep fat fryer witha minimum tendency to clog.

Still another object is to provide a filter unit that can be readilymanufactured at low cost.

Other objects and advantages of the invention will be apparent from thefollowing description taken in conjunction with the accompanyingdrawings.

DESCRIPTION or THE DRAWINGS FIG. 1 is a plane view of one embodiment ofthe present filter unit illustrated in full lines, and shown mounted ina housing or receptacle illustrated in dot-and-dash lines;

FIG. 2 is an enlarged vertical sectional view through the filter unitand housing, taken on the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary sectional view through one of the sections of afilter element, taken on the line 3--3 of FIG. 1, and particularlyillustrating the shape of one of the stiffening ribs;

FIG. 4 is an elevational view of the filter shown in FIG. 2;

FIG. 5 is a vertical sectional view through a second embodiment of thefilter unit consisting of one filter element; and

FIG. 6 is a vertical sectional view through a third embodiment of thefilter unit consisting of two filter elements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 4, thefilter unit is generally identified by the numeral 2 and comprises atubular carbon steel core 4 having internal threads 6 at its lower endterminating at a shoulder 8. A stainless steel disc 10 is welded to theupper end of the core 4 at its circumference, as indicated at 12. Thedisc 10 has an opening 14, in which the lower end of the shank 16 of aT-shaped handle 18 is secured by a continuous weld, as indicated at 20.A stainless steel ring 22 is welded at its inner circumference to thecore 4 near the lower end thereof, as indicated at 24. A plurality ofradial openings 26 is drilled through the core 4, tangent with the uppersurface of the ring 22, to facilitate draining of all liquid from theinterior of the filter unit 2.

The filter unit 2 comprises one or more filter elements 28, four suchelements 28 being shown in FIG. 2, it being understood that any numberof elements can be employed, depending upon the environment, in whichthe filter unit 2 is to be used. Each filter element 28 comprises twoidentical annular diaphragms or sections, an upper section 30 and alower section 32. The sections 30 and 32 are preferably made ofstainless steel woven wire mesh material providing openings of a sizethat will prevent passage therethrough of particles as small as 160microns. Stainless steel wire 0.016 inches and 0.01 1 inches in diameteris used to provide a 24 X 110 mesh. A coating of Teflon applied to themesh material reduces the size of the openings therein to about microns,thus enabling the same to filter out smaller particles than when thecoating is omitted, as may be done in some instances.

As is best shown in FIG. 2, the filter sections 30 and 32 are each oftruncated cone shape, or dished, and are disposed with the concave sidesthereof confronting each other. Both sections 30 and 32 have flatmarginal or rim portions 34 and 36, respectively, that contact eachother and are welded or fused together throughout their peripheraledges, as indicated at 38. Adjoining each of the rim portions 34, 36 isan annular stiffening portion 40 that is disposed on an angle of about45 to the horizontal plane of the sections 30, 32. Each of the lowersections 32 has a flat inner marginal portion 42, and each of the uppersections 30 has a flat inner marginal portion 44. The adjacent marginalportions 42 and 44 contact and are welded or fused together throughouttheir periphery, as indicated at 45. The inner rim portion 44 of theuppermost section 30 is circumferentially welded to the disc 10, asindicated at 46, and the inner rim portion 42 of the lowermost section32 is circumferentially welded to the ring 22, as indicated at 48.Adjoining each of the inner rim portions 42, 44, is an annularstiffening portion 49 inclined on an angle of about 45 to thehorizontal. Between the stiffening portions 48 and 49 is a relativelylarge annular portion 51 inclined on an angle of about 3 to thehorizontal. This design makes it easy to get access to the spaces 52between adjacent sections for cleaning purposes. The diameter of theinner edges of the marginal portions 42 and 44 is greater than theoutside diameter of the core 4, so that when a plurality of filterelements 28 is employed, they are all in free communication with eachother throughout the height of the core 4 and are also in communicationwith the openings 26.

Referring to FIG. 3, each of the sections 30, 32 has a series ofexternal radial deformations 53 in the annular area 51 that serve asstiffening ribs functioning to retain the sections in a dishedcondition, and aid in preventing collapse of the sections as the liquidbeing filtered is drawn therethrough.

The filter unit 2 can be mounted in any suitable housing or receptacle,and by way of example, a housing 54 is shown in dot-and-dash lines withthe filter unit 2 mounted within it. The housing 54 includes a side wall56 and a bottom wall 58. An externally threaded outlet fitting 60projects upwardly into the housing and is received in the threadedopening 6 of the core 4, with the upper end of the fitting tightlyabutting against the shoulder 8 to form a seal. The side wall 56 maydepend from the bottom wall 62 of another container 64, which, forexample, may be a cooking pot of a deep fat fryer, in which event thehousing 54 may be considered a filter bowl. The open end of the housing54 may be closed by a cover plate 66 having openings 68 through whichliquid, such as cooking oil, having entrained solids can enter thehousing 54.

A suction pipe 70 is connected with the fitting 60 exteriorly of thehousing 54 and may be connected with a pump (not shown) as will bereadily understood. Contaminated liquid entering the housing 54 will bedrawn through the filter elements 28 by the pump, and any solid matterentrained in the liquid will be prevented from passing through thefilter elements to the interior of the filter elements and will thuseither be collected in the housing 54 or be deposited on the filterelements 28.

The liquid entering the filter unit 2 through the minute openings in thefilter sections 28 will enter the space surrounding the core 4, and passout of the filter unit through the openings 26 and into the fitting 60for discharge through the pipe 70. The filtered liquid may be returnedby the pump to the container 64 by means not shown.

The present filter unit with its foraminous elements is not limited touse in any particular environment as will be readily understood.However, it is particularly adapted to be used to filter the cooking oilin a deep fat fryer, which invariably contains batter and other foodparticles that will carbonize and shorten the life of the cooking oil,unless completely removed. For example, the present filter unit may beemployed in a deep fat fryer of the type disclosed in Quednau, US. Pat.No. 3,4l0,l99.

The filter sections 30 and 32 are preferably coated with Teflon toprevent solids, and particularly hot solids, from sticking to thesurfaces thereof, and to thus facilitate cleaning of the filter unit.The presence of the Teflon also reduces any tendency for the filter toclog.

Whenever it is desired to clean the filter unit 2, the housing 54 isdrained to at least the level of the openings 26 in the core 4. Sincethese openings are located at the lowest possible level within thefilter unit 2, all liquid will be drained from the interior of saidunit. After the liquid has been drained, the handle 18 can be rotated tounscrew the filter unit 2 from the fitting 60, so that the unit 2 can bebodily removed and cleaned. Since the filter sections 30 and 32 areTeflon coated, foreign particles will not adhere thereto and this isespecially true of batter and other residue present in hot cooking oil.The filter unit 2 can be immersed in hot water containing a milddetergent and thoroughly washed and cleaned with a brush if necessaryand then flushed out with clear water and remounted in the housing 54.The ample space 52 between the filter elements 28 makes it easy to getto the innermost portion of the spaces to remove any solids that mayhave become lodged there.

FIG. illustrates another embodiment of the invention in which a singlefilter element 28 is employed with a relatively shorter core 4. Otherparts shown corresponding to those described above have been identifiedby the same reference characters.

FIG. 6 illustrates a third embodiment of the invention comprising twofilter elements 28, with other parts previously described identified bycorresponding reference numerals. FIG. 2, which shows four filterelements 28 will adequately serve to illustrate the manner in which anydesired number of filter elements 28 can be assembled to provide afilter unit of any desired capacity.

The above-described filter units are easy to install and remove, arehighly efiicient, can be easily cleaned when necessary and are ruggedlyconstructed to resist damage in handling and collapse in normal use.Thus, a long and satisfactory life of the filter unit is assured,avoiding any necessity for frequent replacement.

It will be understood that minor changes may be made in the details ofdesign and construction of the filter units disclosed herein and in thecharacter of the foraminous material used, without departing from theprinciples of the invention or the scope of the annexed claims.

We claim:

1. A filter unit to be removably mounted in a housing having an upperend with an inlet opening and a bottom wall with a threaded outletopening, comprising: a tubular core closed at its upper end and havingan open, threaded lower end for connecting the same to said threadedoutlet opening; and at least one filter element mounted upon said core,the filter element comprising two annular, frusto-conical sectionssurrounding said core and disposed in confronting relation, saidsections being made of wire mesh filter material and including flatinner and outer marginal portions and an annular stifiening portionadjacent each of said flat marginal portions inclined at an angle to theplane of the sections, said sections having their outer marginspermanently connected together, said core having openings extendingtherethrough communicating with the interior of said filter element.

2. A filter unit as defined in claim 1, in which the sections of thefilter element each have outwardly displaced radial stiffening ribsdisposed between the inclined annular stiffening portions.

3. A filter unit as defined in claim I, in which the core is closed atits upper end by a disc permanently secured thereto.

4. A filter unit as defined in claim 3, in which a handle is secured tothe disc.

5. A filter unit as defined in claim 1, in which the core is internallythreaded and the threads terminate at a shoulder projecting inwardlybeyond said threads.

6. A filter unit as defined in claim 1, in which a single filter elementis mounted upon the core and the inner margins of the sections of saidfilter element are welded to the core.

7. A filter unit as defined in claim 1, in which a plurality of filterelements are mounted upon the core, and wherein the inner marginal edgesof the sections comprising said filter elements, except the topmost andlowermost sections, are spaced from said core, and wherein the innermarginal edges of adjacent sections are secured together.

8. A filter unit as defined defined in claim 7, in which the core isclosed at one end by a disc, and the upper section of the uppermostfilter elements is secured to said disc.

9. A filter unit as defined in claim 8, wherein a ring is secured to thecore near the open end thereof, and the lower section of the lowermostfilter element is secured to said ring.

10. A filter unit as defined in claim 9, in which the openings in thecore are in a plane adjacent to the upper face of the ring.

1 l. A filter unit, comprising: a tubular core; a plurality of filterelements mounted upon said core, each filter element comprising twodished sections disposed in spaced confronting relation, said sectionsbeing made of foraminous material, the sections of each element havingtheir outer margins connected together; a disc forming a closure for oneend of said core, the section of the uppermost filter element having aninner marginal portion secured to said disc; a ring mounted upon saidcore near the other end thereof, the lower section of the lowermostfilter element being secured to said ring, the

sections of the filter elements between said upper and lower section ofsaid uppermost and lowermost filter elements having inner marginalportions spaced from said core, with the inner margin portions ofadjacent sections secured together, said core having a plurality ofradial openings extending therethrough in a plane adjacent to the upperface of said ring, said other end of said core being internally threadedwith the threads terminating at an inwardly projecting shoulder; and ahandle secured to said disc to facilitate mounting said filter unit on,and removing the same from, a threaded support.

12. A filter unit, comprising: a tubular core closed at one end and openat its other end; and one or more filter elements mounted upon saidcore, each filter element comprising an upper and a lower frusto-conicalsection surrounding said core and disposed in confronting relation toeach other, said sections of each filter element being made offoraminous material and having their outer margins permanently connectedtogether, said core having a single row of openings extendingtherethrough communicating with the interior of the filter elementnearest to the open end of the core and being located closest to thelower section of the filter element nearest to the open end of saidcore.

1. A filter unit to be removably mounted in a housing having an upperend with an inlet opening and a bottom wall with a threaded outletopening, comprising: a tubular core closed at its upper end and havingan open, threaded lower end for connecting the same to said threadedoutlet opening; and at least one filter element mounted upon said core,the filter element comprising two annular, frusto-conical sectionssurrounding said core and disposed in confronting relation, saidsections being made of wire mesh filter material and including flatinner and outer marginal portions and an annular stiffening portionadjacent each of said flat marginal portions inclined at an angle to theplane of the sections, said sections having their outer marginspermanently connected together, said core having openings extendingtherethrough communicating with the interior of said filter element. 2.A filter unit as defined in claim 1, in which the sections of the filterelement each have outwardly displaced radial stiffening ribs disposedbetween the inclined annular stiffening portions.
 3. A filter unit asdefined in claim 1, in which the core is closed at its upper end by adisc permanently secured thereto.
 4. A filter unit as defined in claim3, in which a handle is secured to the disc.
 5. A filter unit as defineDin claim 1, in which the core is internally threaded and the threadsterminate at a shoulder projecting inwardly beyond said threads.
 6. Afilter unit as defined in claim 1, in which a single filter element ismounted upon the core and the inner margins of the sections of saidfilter element are welded to the core.
 7. A filter unit as defined inclaim 1, in which a plurality of filter elements are mounted upon thecore, and wherein the inner marginal edges of the sections comprisingsaid filter elements, except the topmost and lowermost sections, arespaced from said core, and wherein the inner marginal edges of adjacentsections are secured together.
 8. A filter unit as defined defined inclaim 7, in which the core is closed at one end by a disc, and the uppersection of the uppermost filter elements is secured to said disc.
 9. Afilter unit as defined in claim 8, wherein a ring is secured to the corenear the open end thereof, and the lower section of the lowermost filterelement is secured to said ring.
 10. A filter unit as defined in claim9, in which the openings in the core are in a plane adjacent to theupper face of the ring.
 11. A filter unit, comprising: a tubular core; aplurality of filter elements mounted upon said core, each filter elementcomprising two dished sections disposed in spaced confronting relation,said sections being made of foraminous material, the sections of eachelement having their outer margins connected together; a disc forming aclosure for one end of said core, the section of the uppermost filterelement having an inner marginal portion secured to said disc; a ringmounted upon said core near the other end thereof, the lower section ofthe lowermost filter element being secured to said ring, the sections ofthe filter elements between said upper and lower section of saiduppermost and lowermost filter elements having inner marginal portionsspaced from said core, with the inner margin portions of adjacentsections secured together, said core having a plurality of radialopenings extending therethrough in a plane adjacent to the upper face ofsaid ring, said other end of said core being internally threaded withthe threads terminating at an inwardly projecting shoulder; and a handlesecured to said disc to facilitate mounting said filter unit on, andremoving the same from, a threaded support.
 12. A filter unit,comprising: a tubular core closed at one end and open at its other end;and one or more filter elements mounted upon said core, each filterelement comprising an upper and a lower frusto-conical sectionsurrounding said core and disposed in confronting relation to eachother, said sections of each filter element being made of foraminousmaterial and having their outer margins permanently connected together,said core having a single row of openings extending therethroughcommunicating with the interior of the filter element nearest to theopen end of the core and being located closest to the lower section ofthe filter element nearest to the open end of said core.